Banknote thickness identification is an important detection method in the process of banknote negotiability identifying in the field of existing financial self-service equipment. At present commonly used mechanical contact identification method for valuable paper is mainly implemented through relative rotation of a driving part and a driven part, where the driving part is a thickness driving shaft and the driven part includes a shaft and a floating part arranged on the shaft, with surface of the floating part tangently contacting with the thickness driving shaft under the action of external pressure and can float up and down with variation of banknote thickness, therefore thickness of the banknote can be detected.
However, surfaces of the thickness driving shaft and the driven shaft are very smooth due to the requirement of machining precision of the mechanical contact valuable paper thickness identification device meanwhile the driving device drives the driven device to rotate, therefore slip occurs during the rotation process, making a same point of the thickness driving shaft tangent with arbitrary point on the surface of the driven shaft, output phase having no regularity and no periodical variation, resulting in an inaccurate thickness detecting result. In addition, slip between the thickness driving shaft and the driven shaft makes sliding friction occur to surface of the shaft during the rotation process, which accelerates abrasion of shaft surface and degrades the accuracy, consequently, a same detected object with a uniform thickness is measured to have inconsistent results in different time quantum, that is to say, slip problem brings error to valuable paper thickness detection, degrades thickness detecting accuracy and adversely affects detection rate of the financial equipment.